Spacecraft missions have observed regolith blankets of unconsolidated subcentimetre particles on stony asteroids
. Telescopic data have suggested the presence of regolith blankets also on ...carbonaceous asteroids, including (101955) Bennu
and (162173) Ryugu
. However, despite observations of processes that are capable of comminuting boulders into unconsolidated materials, such as meteoroid bombardment
and thermal cracking
, Bennu and Ryugu lack extensive areas covered in subcentimetre particles
. Here we report an inverse correlation between the local abundance of subcentimetre particles and the porosity of rocks on Bennu. We interpret this finding to mean that accumulation of unconsolidated subcentimetre particles is frustrated where the rocks are highly porous, which appears to be most of the surface
. The highly porous rocks are compressed rather than fragmented by meteoroid impacts, consistent with laboratory experiments
, and thermal cracking proceeds more slowly than in denser rocks. We infer that regolith blankets are uncommon on carbonaceous asteroids, which are the most numerous type of asteroid
. By contrast, these terrains should be common on stony asteroids, which have less porous rocks and are the second-most populous group by composition
. The higher porosity of carbonaceous asteroid materials may have aided in their compaction and cementation to form breccias, which dominate the carbonaceous chondrite meteorites
.
IR spectroscopy is an excellent method for biological analyses. It enables the nonperturbative, label-free extraction of biochemical information and images toward diagnosis and the assessment of cell ...functionality. Although not strictly microscopy in the conventional sense, it allows the construction of images of tissue or cell architecture by the passing of spectral data through a variety of computational algorithms. Because such images are constructed from fingerprint spectra, the notion is that they can be an objective reflection of the underlying health status of the analyzed sample. One of the major difficulties in the field has been determining a consensus on spectral pre-processing and data analysis. This manuscript brings together as coauthors some of the leaders in this field to allow the standardization of methods and procedures for adapting a multistage approach to a methodology that can be applied to a variety of cell biological questions or used within a clinical setting for disease screening or diagnosis. We describe a protocol for collecting IR spectra and images from biological samples (e.g., fixed cytology and tissue sections, live cells or biofluids) that assesses the instrumental options available, appropriate sample preparation, different sampling modes as well as important advances in spectral data acquisition. After acquisition, data processing consists of a sequence of steps including quality control, spectral pre-processing, feature extraction and classification of the supervised or unsupervised type. A typical experiment can be completed and analyzed within hours. Example results are presented on the use of IR spectra combined with multivariate data processing.
The Southern Parkes Large-Area Survey in Hydroxyl (SPLASH) is a sensitive, unbiased, and fully sampled survey of the southern Galactic plane and Galactic Centre in all four ground-state transitions ...of the hydroxyl (OH) radical. The survey provides a deep census of 1612-, 1665-, 1667-, and 1720-MHz OH absorption and emission from the Galactic interstellar medium, and is also an unbiased search for maser sources in these transitions. We present here first results from the SPLASH pilot region, which covers Galactic longitudes 334° to 344° and latitudes ±2°. Diffuse OH is widely detected in all four transitions, with optical depths that are always small (averaged over the Parkes beam), and with departures from local thermodynamic equilibrium common even in the 1665- and 1667-MHz main lines. To a 3σ sensitivity of ∼30 mK, we find no evidence of OH envelopes extending beyond the CO-bright regions of molecular cloud complexes, and conclude that the similarity of the OH excitation temperature and the level of the continuum background is at least partly responsible for this. We detect masers and maser candidates in all four transitions, approximately 50 per cent of which are new detections. This implies that SPLASH will produce a substantial increase in the known population of ground-state OH masers in the southern Galactic plane.
Visible-wavelength color and reflectance provide information about the geologic history of planetary surfaces. Here we present multispectral images (0.44 to 0.89 micrometers) of near-Earth asteroid ...(101955) Bennu. The surface has variable colors overlain on a moderately blue global terrain. Two primary boulder types are distinguishable by their reflectance and texture. Space weathering of Bennu surface materials does not simply progress from red to blue (or vice versa). Instead, freshly exposed, redder surfaces initially brighten in the near-ultraviolet region (i.e., become bluer at shorter wavelengths), then brighten in the visible to near-infrared region, leading to Bennu’s moderately blue average color. Craters indicate that the time scale of these color changes is ~105 years. We attribute the reflectance and color variation to a combination of primordial heterogeneity and varying exposure ages.
In this paper, we review recent theoretical progress and the latest experimental results in jet substructure from the Tevatron and the LF1C. We review the status of and outlook for calculation and ...simulation tools for studying jet substructure. Following up on the report of the Boost 2010 workshop, we present a new set of benchmark comparisons of substructure techniques, focusing on the set of variables and grooming methods that are collectively known as 'top taggers'. To facilitate further exploration, we have attempted to collect, harmonize and publish software implementations of these techniques.
We hypothesized that chemoprophylaxis with the echinocandin micafungin would be an effective agent for antifungal prophylaxis during neutropenia in patients undergoing hematopoietic stem cell ...transplantation (HSCT). We therefore conducted a randomized, double-blind, multi-institutional, comparative phase III trial, involving 882 adult and pediatric patients, of 50 mg of micafungin (1 mg/kg for patients weighing <50 kg) and 400 mg of fluconazole (8 mg/kg for patients weighing <50 kg) administered once per day. Success was defined as the absence of suspected, proven, or probable invasive fungal infection (IFI) through the end of therapy and as the absence of proven or probable IFI through the end of the 4-week period after treatment. The overall efficacy of micafungin was superior to that of fluconazole as antifungal prophylaxis during the neutropenic phase after HSCT (80.0% in the micafungin arm vs. 73.5% in the fluconazole arm difference, 6.5%; 95% confidence interval, 0.9%-12%; P = .03). This randomized trial demonstrates the efficacy of an echinocandin for antifungal prophylaxis in neutropenic patients.
We present first results of the H2O Southern Galactic Plane Survey (HOPS), using the Mopra Radio Telescope with a broad-band backend and a beam size of about 2 arcmin. We have observed 100 deg2 of ...the southern Galactic plane at 12 mm (19.5-27.5 GHz), including spectral line emission from H2O masers, multiple metastable transitions of ammonia, cyanoacetylene, methanol and radio recombination lines. In this paper, we report on the characteristics of the survey and H2O maser emission. We find 540 H2O masers, of which 334 are new detections. The strongest maser is 3933 Jy and the weakest is 0.7 Jy, with 62 masers over 100 Jy. In 14 maser sites, the spread in the velocity of the H2O maser emission exceeds 100 km s−1. In one region, the H2O maser velocities are separated by 351.3 km s−1. The rms noise levels are typically between 1 and 2 Jy, with 95 per cent of the survey under 2 Jy. We estimate completeness limits of 98 per cent at around 8.4 Jy and 50 per cent at around 5.5 Jy. We estimate that there are between 800 and 1500 H2O masers in the Galaxy that are detectable in a survey with similar completeness limits to HOPS. We report possible masers in NH3 (11,9) and (8,6) emission towards G19.61−0.23 and in the NH3 (3,3) line towards G23.33−0.30.
In the ProtecT trial, over 1600 men with PSA-detected localized prostate cancer were assigned to active monitoring, prostatectomy, or radiotherapy. Although more patients assigned to active ...monitoring had disease progression, overall survival was similar in the three groups.
The management of clinically localized prostate cancer that is detected on the basis of prostate-specific antigen (PSA) levels remains controversial. In the United States alone, an estimated 180,890 cases will be diagnosed in 2016, and 26,120 men will die from the disease.
1
The widespread use of PSA testing has resulted in a dramatic increase in the diagnosis and treatment of prostate cancer, but many men do not benefit from intervention because the disease is either indolent or disseminated at diagnosis. Prostate cancer often progresses slowly, and many men die of competing causes. In addition, interventions for prostate cancer can have . . .
The use of conventional chemical insecticides and bacterial toxins to control lepidopteran pests of global agriculture has imposed significant selection pressure leading to the rapid evolution of ...insecticide resistance. Transgenic crops (e.g., cotton) expressing the Bt Cry toxins are now used world wide to control these pests, including the highly polyphagous and invasive cotton bollworm Helicoverpa armigera. Since 2004, the Cry2Ab toxin has become widely used for controlling H. armigera, often used in combination with Cry1Ac to delay resistance evolution. Isolation of H. armigera and H. punctigera individuals heterozygous for Cry2Ab resistance in 2002 and 2004, respectively, allowed aspects of Cry2Ab resistance (level, fitness costs, genetic dominance, complementation tests) to be characterised in both species. However, the gene identity and genetic changes conferring this resistance were unknown, as was the detailed Cry2Ab mode of action. No cross-resistance to Cry1Ac was observed in mutant lines. Biphasic linkage analysis of a Cry2Ab-resistant H. armigera family followed by exon-primed intron-crossing (EPIC) marker mapping and candidate gene sequencing identified three independent resistance-associated INDEL mutations in an ATP-Binding Cassette (ABC) transporter gene we named HaABCA2. A deletion mutation was also identified in the H. punctigera homolog from the resistant line. All mutations truncate the ABCA2 protein. Isolation of further Cry2Ab resistance alleles in the same gene from field H. armigera populations indicates unequal resistance allele frequencies and the potential for Bt resistance evolution. Identification of the gene involved in resistance as an ABC transporter of the A subfamily adds to the body of evidence on the crucial role this gene family plays in the mode of action of the Bt Cry toxins. The structural differences between the ABCA2, and that of the C subfamily required for Cry1Ac toxicity, indicate differences in the detailed mode-of-action of the two Bt Cry toxins.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Carbonaceous asteroids, such as (101955) Bennu, preserve material from the early Solar System, including volatile compounds and organic molecules. We report spacecraft imaging and spectral data ...collected during and after retrieval of a sample from Bennu’s surface. The sampling event mobilized rocks and dust into a debris plume, excavating a 9-meter-long elliptical crater. This exposed material is darker, spectrally redder, and more abundant in fine particulates than the original surface. The bulk density of the displaced subsurface material was 500 to 700 kilograms per cubic meter, which is about half that of the whole asteroid. Particulates that landed on instrument optics spectrally resemble aqueously altered carbonaceous meteorites. The spacecraft stored 250 ± 101 grams of material, which will be delivered to Earth in 2023.
Grabbing a sample of asteroid Bennu
The near-Earth carbonaceous asteroid Bennu was the target of the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) sample return mission. After rendezvousing with the asteroid, the spacecraft spent 2 years studying its surface and selecting a suitable site. Lauretta
et al
. describe the sample collection process and its effects on Bennu. The asteroid provided almost no resistance to contact, and the gas released by the spacecraft blew a crater several meters wide, exposing redder rocks and dust. So much material was gathered that the collection chamber overflowed. Approximately 250 grams was successfully stowed, well above the mission goal of 60 grams. The samples are expected to arrive on Earth in September 2023. —KTS
Samples of the near-Earth asteroid Bennu were collected by the OSIRIS-REx mission and should arrive on Earth in 2023.
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